The switching and routing of signals between antennas and receivers/transmitters is a significant problem which must be addressed during the design and construction of multiple beam antenna systems. This is particularly true in "smart" multiple beam antenna systems where the goal is to couple the optimal antenna with an associated radio receiver or transmitter. While techniques are currently available for routing and switching signals in multiple beam antenna systems, they are typically complex, expensive to implement and require substantial amounts of hardware.
In general, the size, complexity and expense of the switching and routing system in a multiple beam antenna system is directly proportional to the number of antennas times the number of associated radios (receiver/transmitters). For example, in a typical cellular communications system, two antennas, a sector antenna and a diversity antenna, are provided per face. In some systems three "faces" are used, each of which covers a corresponding 120.degree. sector of a 360.degree. total field of view. In other systems, a single face may be used covered by an omnidirectional sector antenna and an omnidirectional diversity antenna. In each case, a transmit cable and/or a receive cable is required for every antenna beam employed. In multiple beam systems, such as the systems shown in Copending patent application Ser. No. 08/488,793, filed Jun. 8, 1995, Titled: NARROW BEAM ANTENNA SYSTEMS WITH ANGULAR DIVERSITY, now issued as U.S. Pat. No. 5,563,610, and Ser. No. 08/520,316, filed Aug. 28, 1995, Titled: APPARATUS, SYSTEMS AND METHODS FOR MULTIPLE ANTENNA TRANSMISSION IN WIRELESS COMMUNICATIONS SYSTEMS, and now U.S. Pat. No. 5,648,968 which are hereby incorporated by reference herein, where each face is covered by a number of narrow beams, the number of cables correspondingly increases. In these systems, anywhere from 12 to 40 separate antennas may be used per channel with perhaps 30-60 channels per cell site. In some situations, the ideal placement of antennas for a "cell site" might be hundreds of feet separated on diverse corners of a block square building. Using existing technology, this antenna placement becomes prohibitively expensive. Each cable may be between fifty to two hundred feet in length and cost several dollars per foot. Longer separations are impractical due to cable losses at RF frequencies.
The typical cellular communications system includes fifteen to twenty radios (receivers/transmitters) per face, with each radio being tuned to a given frequency (channel). Hence, notwithstanding the problem of cabling discussed above, the system switching matrix also becomes more complicated and expensive proportionate to the number of antenna beams and number of radios. For each face, one path must be provided from every antenna to every radio. In some embodiments, the capability must exist for any radio to be connected to any beam in any face. Consequently, for M number of radios, an M-way power divider is required per antenna. Further, for every radio there must be an N-way selector switch to couple that radio to a given one of the N number of antenna beams. In sum, for a system with M number of radios and N number of antennas, an M by N switching matrix is required. As the matrix grows larger and the component count grows, the reliability and mean time between failure decrease, while the cost and physical size of the switching system increases.
Thus, the need has arisen for improved apparatus, systems and methods for routing and switching signals between a multiple beam antenna system to one or more associated radios. Such apparatus, systems and methods should reduce the cost and complexity of switching and routing signals to and from the beams of multiple beam antenna systems, especially "smart" multiple beam antenna systems. Increases in system reliability and the ability to construct a more compact beam switching/routing system would also be advantageous. In some cases more antenna beams would be desirable, but is constrained by the number of cables; for example, in a situation where the cables are inside a hollow pipe.